Multiplex pump systems and associated methods of use with waterjet systems and other high pressure fluid systems

ABSTRACT

High pressure pump systems for use with waterjet systems and other systems are described herein. A pump system configured in accordance with a particular embodiment includes a first multi-cylinder pump having a first crankshaft and a second multi-cylinder pump having a second crankshaft. The first and second crankshafts are operably coupled together (via, e.g., a common drive system) so that the reciprocation cycles of the corresponding pistons or plungers are spaced apart from each other in equal intervals of crankshaft rotation.

CROSS-REFERENCE TO APPLICATION(S) INCORPORATED BY REFERENCE

This application claims the benefit of U.S. Provisional Application No. 61/941,238, filed Feb. 18, 2014. U.S. Provisional Application No. 61/941,238, and U.S. patent application Ser. No. 14/164,062, filed on Jan. 24, 2014, are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure is directed generally to high and ultrahigh pressure pump systems and associated methods for use with fluid-jet systems and other systems.

BACKGROUND

There are various commercial and industrial uses for high pressure fluid pump systems operating at pressures greater than 20,000 psi. Such pump systems can be used in, for example, fluid-jet cutting systems, fluid-jet cleaning systems, etc. Fluid-jet cutting systems often use reciprocating, positive displacement pumps (e.g., crankshaft-driven plunger pumps). Crankshaft-driven plunger pumps, such as triplex plunger pumps (i.e., pumps having three cylinders and associated plungers) operating at outlet pressures of 20,000 psi or more produce pressure pulsations caused by the cyclic output from the pump cylinders. These pressure pulsations can produce undesirably high levels of pressure ripple downstream from the pump. The pressure ripple can be partially mitigated by use of a pump output manifold that contains a volume of the high pressure fluid before it flows to downstream applications.

Conventional low pressure crankshaft-driven, reciprocating positive displacement pumps operating at outlet pressures of 7,500 psi or less typically use pistons instead of plungers. One reason for this is that piston pumps generally have much higher volumetric efficiencies that plunger pumps. Piston pumps, however, can also create significant pressure pulsation during operation. As a result, such pumps are typically used with pulsation dampeners to reduce pressure ripple downstream of the pump. Pulsation dampeners typically include a vessel having a resilient diaphragm with a gas (such as nitrogen) on one side of the diaphragm and the media being pumped (e.g., water) on the opposite side of the diaphragm. In operation, water discharged from the pump flows into the dampener vessel, with the diaphragm alternatingly expanding and compressing the gas as the water pressure increases, and then contracting and letting the gas expand against the water as the water flows out of the vessel and the pressure decreases. Pulsation dampeners are usually attached directly to the output manifold of the pump. In this way, dampeners can reduce pressure pulsations in the water downstream from the pump.

Gas filled pulsation dampeners tend to lose effectiveness as output pressures increase and the gas begins to go through a phase change to a liquid or supercritical fluid. As noted above, high pressure pumps typically rely primarily on the volume of fluid in the output manifold to reduce pressure ripple. Pressure attenuators can also be used to mitigate pump pressure ripple. Pressure attenuators are essentially pressure vessels that accumulate the high pressure water from the pump cylinders to dampen pressure fluctuations in the water as it is provided to, for example, a fluid-jet cutting head or other downstream application. Pressure attenuators are generally placed as close to the pump as possible, but even with relatively large attenuators, these systems can still experience relatively large pressure fluctuations during pump operation that results in downstream pressure ripple.

Fluid-jet systems (e.g., waterjet or abrasive jet systems) are one of the areas of technology that utilize ultrahigh pressure pumps. Fluid-jet systems can be used in precision cutting, shaping, carving, reaming, and other material-processing applications. The liquid most frequently used to form the jet is water, and the high-velocity jet may be referred to as a “water jet” or “waterjet.” In operation, waterjet systems typically direct a high-velocity jet of water toward a workpiece to rapidly erode portions of the workpiece. Abrasive material can be added to the fluid to increase the rate of erosion. When compared to other shape-cutting systems (e.g., electric discharge machining (EDM), laser cutting, plasma cutting, etc.), waterjet systems can have significant advantages. For example, waterjet systems often produce relatively fine and clean cuts, typically without heat-affected zones around the cuts. Waterjet systems also tend to be highly versatile with respect to the material type of the workpiece. The range of materials that can be processed using waterjet systems includes very soft materials (e.g., rubber, foam, leather, and paper) as well as very hard materials (e.g., stone, ceramic, and hardened metal). Furthermore, in many cases, waterjet systems are capable of executing demanding material-processing operations while generating little or no dust, smoke, and/or other potentially toxic byproducts.

In a typical waterjet system, a pump pressurizes water to a high pressure (e.g., up to 60,000 psi or more), and the water is routed from the pump to a cutting head that includes an orifice. Passing the water through the orifice converts the static pressure of the water into kinetic energy, which causes the water to exit the cutting head as a jet at high velocity (e.g., up to 2,500 feet per second or more) and impact a workpiece. In many cases, a jig supports the workpiece. The jig, the cutting head, or both can be movable under computer and/or robotic control such that complex processing instructions can be executed automatically.

The pressure ripple produced by conventional crankshaft-driven plunger pumps used in waterjet systems have a number of disadvantages. For example, the pulsations can cause vibration and fatigue in the fluid conduits and other components that make up the high pressure fluid circuit between the pump and the cutting head. Additionally, the pressure pulses can cause vibration of the cutting head, which adversely affects the waterjet cutting quality. As discussed above, methods for mitigating pressure ripple typically include increasing the volume of the pump manifold or adding a pressure attenuator to the system. Although somewhat effective, neither approach is an ideal solution. Pressure manifolds typically have cross-bores that receive the output flow from each pump cylinder. The cross-bores within the manifold can create areas of high stress concentrations that limit component life due to eventual fatigue failure. In addition, pressure manifolds can be relatively expensive to manufacture, and the cost generally increases as the size of the manifold increases. As noted, some pumps are fitted with pressure attenuators to reduce pressure ripple and mitigate the disadvantages discussed above. As with pressure manifolds, however, large pressure attenuators can also be costly to manufacture due to component size. Although attenuators do not have cross-bores, they are also subject to fatigue failure. In addition, increasing the volume of pressurized water stored in a pressure manifold or attenuator has the downside of increasing stored energy within the pump system. Moreover, neither output manifolds nor pressure attenuators provide the full extent of pulse attenuation desired. Accordingly, it would be desirable to have waterjet pump systems that produce less pressure ripple than conventional pump systems to reduce fatigue failures and enhance cutting quality.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on clearly illustrating the principles of the present technology. For ease of reference, throughout this disclosure identical reference numbers may be used to identify identical or at least generally similar or analogous components or features.

FIG. 1 is a graph illustrating pump manifold pressure ripple versus mean output pressure for different multi-cylinder pump configurations assuming water compressibility and non-ideal check valves.

FIGS. 2A-2D are a series of graphs illustrating pump pressure ripple versus crankshaft angle for the four pump configurations of FIG. 1 operating at a mean output pressure of 60,000 psi.

FIGS. 3A-3C are a series of left isometric, right isometric, and top views, respectively, of a multiplex pump system configured in accordance with an embodiment of the present technology.

FIG. 4A is a partially schematic top view of the multiplex pump system of FIGS. 3A-3C, and FIG. 4B is a schematic end view of a portion of a drive system of the multiplex pump system of FIG. 4A, configured in accordance with an embodiment of the present technology.

FIGS. 5A and 5B are end and side views, respectively, of a phased multiplex pump crankshaft arrangement configured in accordance with an embodiment of the present technology.

FIG. 6 is a partially schematic top view of a multiplex pump having phased crankshafts configured in accordance with another embodiment of the present technology.

FIG. 7 is a partially schematic perspective view of a waterjet system including a multiplex pump configured in accordance with an embodiment of the present technology.

DETAILED DESCRIPTION

The following disclosure describes various embodiments of pump systems for use with, e.g., water, aqueous solutions, etc., that can provide high and ultrahigh pressure fluid with lower magnitude pressure pulses or ripples than conventional pump systems. As used herein, the term “ultrahigh pressure” can refer to pressures of 30,000 psi and higher. In some embodiments of the present technology, the pump systems described herein include a first multi-cylinder pump (e.g., a first crankshaft-driven, positive displacement triplex pump) operably coupled to a second multi-cylinder pump (e.g., a second crankshaft-driven, positive displacement triplex pump) in a manner that arranges the respective crankshafts to provide equal, or at least approximately equal, spacing between pressure pulses in the combined output flow from both pumps. For example, as described in greater detail below, in the case of two triplex pumps, each of which has three compression members (e.g., plungers or pistons) that reciprocate in cycles spaced apart by 120 degree phase angles, the two crankshafts (one from each pump) can be operably coupled to the same drive system so that the six compression members reciprocate in cycles spaced apart by 60 degree phase angles. This arrangement produces six evenly spaced apart pressure ripples occurring during each revolution of the coupled crankshafts, and results in output pressure ripples of substantially less magnitude than would otherwise be achieved if the two pumps were coupled together without regard for the phase relationship between the two crankshafts. Accordingly, the present disclosure describes methods and systems for operably coupling two pumps together to efficiently increase (e.g., double) pump output while simultaneously reducing the magnitude of downstream pressure ripple.

The different pump systems and associated methods described herein can be used in a wide variety of commercial, industrial, and/or home applications including, for example, fluid-jet cutting systems (e.g., waterjet or abrasive-jet systems), fluid-jet cleaning systems, etc. Although the embodiments are disclosed herein primarily or entirely with respect to waterjet applications, other applications in addition to those disclosed herein are within the scope of the present technology. For example, pump systems and related methods configured in accordance with at least some embodiments of the present technology can be useful in various other high-pressure fluid-conveyance systems. Furthermore, waterjet systems configured in accordance with embodiments of the present technology can be used with virtually any liquid media pressurized to 20,000 psi or more, such as water, aqueous solutions, hydrocarbons, glycol, and liquid nitrogen, among others. As such, although the term “waterjet” is used herein for ease of reference, unless the context clearly indicates otherwise, the term refers to a jet formed by any suitable fluid and is not limited exclusively to water or aqueous solutions.

Certain details are set forth in the following description and in FIGS. 1-7 to provide a thorough understanding of various systems and methods embodying this fluid pressurizing innovation. Other details describing well-known aspects of pressurizing devices and systems (e.g., positive displacement pump systems, reciprocating plunger pump systems, intensifier pumps, etc.) and waterjet systems are not set forth in the following disclosure, however, to avoid unnecessarily obscuring the description of the various embodiments. Many of the details, dimensions, angles and other features shown in the Figures are merely illustrative of particular embodiments. Accordingly, other embodiments can have other details, dimensions, angles and features without departing from the spirit or scope of the present technology. In addition, further embodiments can be practiced without several of the details described below. To facilitate the discussion of any particular element, the most significant digit or digits of any reference number generally refers to the Figure in which that element is first introduced. For example, element 100 is first introduced and discussed with reference to FIG. 1.

FIG. 1 presents a graph 100 that contains a series of plots 106 a-106 d illustrating output manifold pressure ripple versus mean output pressure for a series of multiplex positive displacement pumps (e.g., reciprocating plunger pumps having more than two plungers and corresponding cylinders), assuming water compressibility and non-ideal inlet and outlet check valves (e.g., accounting for fluid viscosity and thermal conductivity) associated with each pump cylinder. Manifold pressure ripple in psi is measured on a vertical axis 102, and mean output pressure from the pump manifold (or manifolds) is measured in psi along a horizontal axis 104. In this embodiment, the first plot 106 a illustrates output pressure ripple for a triplex pump (e.g., a plunger pump having three plungers and three corresponding cylinders); the second plot 106 b illustrates pressure ripple for a quadruplex pump (e.g., a plunger pump having four plungers and four corresponding cylinders); the third plot 106 c illustrates pressure ripple for a quintuplex pump (e.g., a plunger pump having five plungers and five corresponding cylinders); and the fourth plot 106 d illustrates pressure ripple for a sextuplex pump (e.g., a plunger pump having six plungers and six corresponding cylinders). As used herein, the term “manifold pressure ripple” refers to the difference between the maximum discharge or outlet manifold pressure and the minimum outlet manifold pressure during a complete operating cycle of the pump (e.g., during 360 degrees of crankshaft rotation). This assumes that the high pressure water from each pump cylinder flows into a common outlet manifold or outlet at which the manifold pressure is measured. The foregoing plots are based on the pumps having evenly spaced apart plunger cycles during operation. For example, the triplex pump has three plunger cycles that occur every crankshaft rotation, and the cycles are separated by equal phase angles (or crankshaft angles) of 120 degrees. Similarly, the quadruplex pump has four plunger cycles that occur every crankshaft rotation, and the cycles are separated by equal phase angles of 90 degrees; and so on for the quintuplex pump (72 degrees) and the sextuplex pump (60 degrees).

The graph 100 illustrates that at pressures of about 7,500 psi or less (e.g., at 4,000 psi), the quadruplex pump (the plot 106 b) exhibits slightly higher pressure ripple than the triplex pump (plot 106 a), and both the quintuplex and sextuplex pumps (plots 106 c and 106 d, respectively) exhibit substantially lower pressure ripple. While both the quintuplex and sextuplex pumps continue this pattern in higher pressure regimes, at pressures above about 8,000 psi (e.g., about 15,000 psi or more), the quadruplex pump increasingly produces a pressure ripple of significantly lower magnitude than that of the comparable triplex pump.

Graphs 210 a-210 d in FIGS. 2A-2D illustrate a series of plots 216 a-216 d of manifold pressure ripple for the triplex, quadruplex, quintuplex, and sextuplex pumps, respectively, of FIG. 1 operating at a mean output pressure of 60,000 psi. As with FIG. 1, the water is assumed to be compressible and the cylinder inlet and outlet check valves are assumed to be non-ideal. As shown in FIG. 2A, manifold outlet pressure is measured along a vertical axis 212 and crankshaft angle is measured along a horizontal axis 214. The first plot 216 a in FIG. 2A illustrates that the triplex pump produces a pressure ripple of approximately 2,777 psi when operating at a mean output pressure of 60,000 psi or about 60,000 psi. In contrast to the low pressure (e.g., 4,000 psi) performance of the quadruplex pump as shown by FIG. 1, the second plot 216 b in FIG. 2B illustrates that the quadruplex pump actually produces a pressure ripple of substantially lower magnitude (i.e., 841 psi) than the triplex pump at the same mean operating pressure of 60,000 psi. As shown by the plots 216 c and 216 d FIGS. 2C and 2D, respectively, the relative behavior of the quintuplex pump and the sextuplex pump at 60,000 psi is similar to the behavior of these two pumps at 4,000 psi. That is, the sextuplex pump produces slightly lower pressure ripple than the quintuplex pump. As FIGS. 1-2D illustrate, the quadruplex, quintuplex, and sextuplex plunger pumps of these embodiments produce lower magnitude pressure ripple than a comparable triplex pump at pressures of about 7,500 psi or more.

FIGS. 3A-3C are a series of left isometric, right isometric, and top views, respectively, of a fluid-pressurizing system 340 configured in accordance with an embodiment of the present technology. In the illustrated embodiment, the fluid-pressurizing system is a multiplex pump system and, more specifically, a sextuplex pump system that includes a first positive displacement triplex pump 343 a having three cylinders 342 a-c, and a second positive displacement triplex pump 343 b having three cylinders 342 d-f. In some embodiments, the first and second triplex pumps 343 a, b can the mirror image of each other and identical, or at least generally similar, in structure and function. For example, in one embodiment the first and second pumps 343 a, b can be at least generally similar in structure and function to EnduroMAX triplex plunger pumps (rated at, e.g., 50 HP), available from OMAX Corporation, 21409 72nd Ave. South, Kent, Wash. 98032. In other embodiments, sextuplex pump systems configured in accordance with the present technology can include other types of suitable triplex pumps having other power ratings.

As described in greater detail below, each triplex pump 343 a, b includes three compression members (e.g., reciprocating plungers) operably coupled to a corresponding crankshaft via three connecting rod journals (not shown), and both of the crankshafts can be simultaneously driven by a single drive system 380. In the illustrated embodiment, the drive system 380 includes a motor 381 (e.g., a 100 HP, 150 HP, or other capacity electric motor (e.g., an AC electric motor), an internal combustion engine, or other suitable motive device) operably coupled to each of the crankshafts via one or more suitable drive members (e.g., a timing belt, chain, gear train, etc.; not shown) that can be covered by a corresponding guard 383 a, b (e.g., a belt guard). A motor controller 326 (e.g., a variable frequency drive) can control electrical power (e.g., facility power) provided to the motor 381.

Referring to FIGS. 3A-3C together, in the illustrated embodiment the sextuplex pump system 340 further includes a fluid conditioning unit 320 (e.g., one or more filters), a fluid supply tank 322, and a low power pump 324 (e.g., a 2 HP pump). In operation, low pressure process fluid (e.g., water) flows into the conditioning unit 320 via an inlet conduit 310, and then from the conditioning unit 320 into the adjacent supply tank 322. The low power pump 324 distributes water from the supply tank 322 into a series of inlet conduits 348 a-f via a series of corresponding outlets 328 a-f on the supply tank 322 (FIG. 3C). The conduits 348 a-f distribute the water to corresponding inlets 358 a-f on the pump cylinders 342 a-f, respectively (the conduits 348 a-f are shown in FIG. 3C, but are omitted from FIGS. 3A and 3B for purposes of illustration). Each inlet 358 a-f can include a corresponding check valve (not shown), e.g., a one-way valve configured to let water flow into the corresponding cylinder 342 a-f but not out. Each of the cylinders 342 a-f can also include a corresponding outlet 368 a-f (FIG. 3A). Each outlet 368 a-f can include a corresponding check valve (not shown), e.g., a one-way valve configured to let water flow out of the corresponding cylinder 342 a-f but not in.

In operation, the reciprocating plungers suck water into the cylinders 342 a-f through the inlets 358 a-f, and then pressurize the water and discharge it out of the cylinders 342 a-f through the outlets 368 a-f. More specifically, in the illustrated embodiment the cylinders 342 a-c of the first triplex pump 343 a cyclically discharge the high pressure water to a first manifold 352 a via corresponding outlet conduits 369 a-c, and the cylinders 342 d-f of the second triplex pump 343 b cyclically discharge the high pressure water to a second manifold 352 b via corresponding outlet conduits 369 d-f. In the illustrated embodiment, the manifolds 352 a, b are pressure vessels that act as reservoirs of the high pressure water cyclically output from the individual pump cylinders. In this regard, the manifolds 352 a, b can be sized to reduce the pressure ripple caused by the cyclical output when the high pressure water is provided to, for example, a fluid-jet cutting head or other downstream application. One advantage of the present technology, however, is that it enables the manifolds 352 a, b to be substantially smaller than would otherwise be required in the absence of this technology. Moreover, in some embodiments it is contemplated that the pump phasing technology disclosed herein can enable the manifolds 352 a, b to be omitted from the sextuplex pump system 340 and/or replaced by a much smaller manifold, with the result that the sextuplex pump system 340 would still provide high pressure water with sufficiently low magnitude pressure ripple for satisfactory use with waterjet processing systems and other downstream applications.

The first manifold 352 a can provide high pressure water to a first inlet 359 a on a fluid junction 356 via a first conduit 355 a, and the second manifold 352 b can similarly provide high pressure water to a second inlet 359 b on the fluid junction 356 via a second conduit 355 b. The junction 356 in turn discharges the combined water output into a conduit 357 from an outlet 361. The high pressure water can flow through the conduit 357 to a downstream application (e.g., a waterjet cutting system) via. Additionally, in the illustrated embodiment the conduit 357 is also coupled in fluid communication to a safety valve 353 and a relief valve 354. More specifically, the high pressure fluid from the junction 356 is provided to both the safety valve 353 and the relief valve 354 as well as the downstream conduit 357. In operation, the safety valve 353 can be configured to open and release pressure in the system if the fluid exceeds a maximum safe operating pressure. The relief valve 354 can be at least generally similar in structure and/or function to one or more of the relief valves described in U.S. patent application Ser. No. 13/969,477, titled “CONTROL VALVES FOR WATERJET SYSTEMS AND RELATED DEVICES, SYSTEMS, AND METHODS,” filed on Aug. 16, 2013, and incorporated herein in its entirety by reference.

In some embodiments, the junction 356 is preferably positioned equidistant between the first manifold 352 a and the second manifold 352 b so that the pressure pulses in the water flowing into the junction 356 from the respective pumps 343 a, b occur at evenly spaced apart intervals. More specifically, in these embodiments the first and second conduits 355 a, b should have the same configuration (e.g., equivalent internal diameters or cross-sectional flow areas, equivalent lengths L₁ and L₂, etc.) so that the pressure ripple characteristics of the two water flows entering the fluid junction 356 are the same, except for the phase shift of 60 degrees (in the case of a sextuplex pump) between the two pressure profiles. Without wishing to be bound by theory, it is expected that maintaining the uniform phase shift between these two water flows facilitates the improved downstream pressure ripple characteristics of the present technology. In some embodiments, the pump cylinders 342 a-f can provide high and/or ultrahigh pressure water to the junction 356 at a pressure suitable for, e.g., waterjet processing. The pressure can be, for example, greater than 20,000 psi (e.g., within a range from 20,000 psi to 150,000 psi), greater than 30,000 psi (e.g., within a range from 30,000 psi to 150,000 psi), greater than 60,000 psi (e.g., within a range from 60,000 psi to 150,000 psi). In other embodiments, the pump cylinders 342 a-f can provide water at a pressure greater than another suitable threshold pressure or within another suitable pressure range.

FIG. 4A is a partially schematic top view of the sextuplex pump system 340 of FIG. 3, and FIG. 4B is a schematic end view of a portion of the drive system 380 of FIG. 3, configured in accordance with an embodiment of the present technology. In the illustrated embodiment, the first triplex pump 343 a includes a first crankcase 444 a that supports the three cylinders 342 a-c, and the second triplex pump 343 b includes a second crankcase 444 b that supports the three cylinders 342 d-f. The first triplex pump 343 a further includes three plungers 466 a-c configured to operably reciprocate within the cylinders 342 a-c, respectively, and the second triplex pump 343 b further includes three plungers 466 d-f configured to operably reciprocate within the cylinders 342 d-f, respectively. More specifically, the first, second, and third plungers 466 a-c are operably coupled (e.g., by connecting rods, etc.) to corresponding first, second, and third rod journals 448 a-c on a first crankshaft 446 a rotatably supported in the first crankcase 444 a, and the fourth, fifth, and sixth plungers 466 d-f are operably coupled to corresponding fourth, fifth, and sixth journals 448 d-f on a second crankshaft 446 b rotatably supported in the second crankcase 444 b. In the illustrated embodiment, the journals 448 a-c on the first crankshaft 446 a are positioned 120 degrees out of phase from each other, and the journals 448 d-f on the second crankshaft 446 b are also positioned 120 degrees out of phase from each other. Although the triplex pumps 343 a, b include plungers, in other embodiments multiplex pumps configured in accordance with the present technology can utilize other types of suitable compression members, such as pistons. Accordingly, the present technology is not limited to use with plunger pumps, and extends to other types of positive placement pumps, including at least high pressure piston pumps.

In the illustrated embodiment, the motor 381 includes a first output shaft portion 484 a and an opposite second output shaft portion 484 b. In some embodiments, the first and second output shaft portions 484 a, b can be opposing end portions of a unitary output shaft (e.g., the motor 381 can be a dual-shaft motor). As a result, the two shaft portions 484 a, b rotate in unison at the same RPM. In the illustrated embodiment, the drive system 380 includes first pulleys 488 a, b (e.g., toothed pulleys, sprockets, etc.) fixedly mounted to the output shaft portions 484 a, b, respectively. Similarly, each of the triplex pumps 343 a, b can include a second pulley 486 a, b (e.g., a toothed pulley, sprocket, etc.) fixedly mounted to an end portion of the crankshaft 446 a, b, respectively. Referring to FIGS. 4A and 4B together, the first output shaft portion 484 a can be operably coupled to the first crankshaft 446 a by means of a first timing belt 482 a that operably engages the first and second pulleys 488 a and 486 a, respectively, and the second output shaft portion 484 b can be operably coupled to the second crankshaft 446 b by means of a second timing belt 482 b that operably engages the first and second pulleys 488 b and 486 b, respectively. In some embodiments, the timing belts 482 a, b are flexible belts having teeth molded onto their inner surfaces which are configured to match complementary teeth on the pulleys 488 a, b and 486 a, b. The belts can be made of, for example, a flexible polymer over a fabric reinforcement. The toothed engagement between the timing belts 482 a, b and the respective pulleys 488 a, b and 486 a, b can ensure that the belts 482 a, b transfer power to the crankshafts 446 a, b without slippage and maintain the desired timing or indexing of the first crankshaft 446 a relative to the second crankshaft 446 b, as described herein. In other embodiments, the motor 381 can be operably coupled to the crankshafts 446 a, b with other direct drive devices for maintaining simultaneous rotation of the crankshafts 446 a, b. These devices can include, for example, drive chains and toothed sprockets, a system of gears, or other suitable drive members.

In one aspect of the present technology, the timing belts 482 a, b are installed on the corresponding pulleys 486 a and 488 a so that the reciprocation cycles of the six plungers 466 a-f are evenly spaced apart to occur 60 degrees out of phase from each other during the simultaneous rotation of the crankshafts 446 a, b. More specifically, in the illustrated embodiment the first crankshaft 446 a is coupled to the first output shaft portion 484 a, and the second crankshaft 446 b is coupled to the second output shaft portion 484 b, so that the two crankshafts are operationally offset from each other by a phase angle of 60 degrees (this arrangement can also be referred to as “clocking” the first crankshaft by 60 degrees relative to the second crankshaft). This arrangement also positions the three individual journals 448 a-c on the first crankshaft 446 a at 60 degree angles relative to the three journals 448 d-f on the second crankshaft 446 b. As a result, the individual reciprocation cycles of the plungers 466 a-f will occur at equal (or at least approximately equal) 60 degree timing intervals during simultaneous rotation of the coupled crankshafts 446 a, b about their respective longitudinal axes 492 a, b.

As stated above, in operation the motor 381 drives the crankshafts 446 a, b, and the reciprocating plungers 466 a-f sequentially suck process fluid (e.g., water) into the cylinders 342 a-f through the inlets 358 a-f, respectively, and then sequentially pressurize the water and discharge it out of the cylinders 342 a-f through the outlets 368 a-f. The high pressure water from the cylinders 342 a-c flows into the first manifold 352 a via outlets 368 a-c, and the high pressure water from the cylinders 342 d-f similarly flows into the second manifold 352 b via outlets 368 d-f. Because of the evenly spaced plunger reciprocation cycles discussed above, the sextuplex pump system 340 provides the same (or generally the same) favorable pump pressure ripple characteristics or profile as represented by the plots 106 d and 216 d discussed above with reference to FIGS. 1 and 2D, respectively. Moreover, phasing the crankshafts 446 a, b in the foregoing manner reduces the pressure ripple or pressure fluctuations in output water pressure produced by the sextuplex pump system 340, as compared to, for example, two triplex pumps that are operably coupled together in random fashion without respect to crankshaft relationship. Another advantage of the multiplex pump configuration discussed above, as compared to a sextuplex pump having six cylinders coupled to a single crankshaft housed in a single crankcase, is that the technology disclosed herein enables a sextuplex pump to be assembled from two commercially available triplex pumps at less expense.

FIG. 5A is an end view of the arrangement of the crankshafts 446 a, b of the sextuplex pump system 340 of FIGS. 3A-4B, and FIG. 5B is a corresponding side view of the crankshaft arrangement, for the purpose of graphically illustrating the positional relationship of the connecting rod journals 448 a-f provided by the 60 degree crankshaft phase relationship described in detail above. As described above, the two crankshafts 446 a, b are operably coupled together in the illustrated relationship via the motor output shaft portions 484 a, b (FIG. 4A). Referring to FIGS. 5A and 5B together, in this embodiment the crankshaft longitudinal axes 492 a, b are coaxially aligned so that they operationally rotate about a common longitudinal axis of rotation 582. As shown by the end view of FIG. 5A, in this example the second connecting rod journal 448 b is positioned at an angle of 0/360 degrees, the first connecting rod journal 448 a is positioned at an angle of 120 degrees, and the third connecting rod journal 448 c is positioned at an angle of 240 degrees relative to a center point 584 of the longitudinal axes of rotation 582. Turning next to the second crankshaft 446 b, the sixth connecting rod journal 448 f is located at an angle of 60 degrees, the fifth connecting rod journal 448 e is located at an angle of 180 degrees, and the fourth connecting rod journal 448 d is located at an angle of 300 degrees relative to the center point 584. As the foregoing discussion illustrates, the 60 degree phase angle between the two crankshafts 446 a, b provides an even 60 degree angular spacing between the individual connecting rod journals 448 a-f and, as a result, provides an even spacing between corresponding pump output pressure pulses during pump operation.

In operation, the individual reciprocation cycles of the six plungers 466 a-f (FIG. 4A) occur at equal 60 degree intervals during simultaneous rotation of the coupled crankshafts 446 a, b. As a result, each of the individual triplex pumps 343 a, b produces a pulse of water into the high pressure output stream three times for every revolution of the corresponding crankshaft 446 a, b, and when the two triplex pumps 343 a, b are operably coupled together as described above, the resulting sextuplex pump system 340 produces six equally (or at least approximately equally) spaced pressure pulses (also referred to herein as ripples) for every simultaneous revolution of the crankshafts 446 a, b, as illustrated by, for example, the graph 210 d of FIG. 2D. As illustrated by, for example, the graph 100 of FIG. 1, the sextuplex pump system 340 favorably produces output (e.g., “manifold”) pressure ripple of lower magnitude than comparable triplex, quadruplex, and quintuplex pumps at mean output pressures ranging from, e.g., 15,000 psi up to 60,000 psi and higher.

Although the longitudinal axes 492 a, b of the individual crankshafts 446 a, b are coaxially aligned in FIGS. 5A and 5B for purposes of illustration, axial alignment of the crankshafts is not required to practice the technology described herein. It is contemplated, for example, that two triplex pumps can be operably coupled together with their two crankshafts operably positioned parallel to each other. The parallel crankshafts of such a system can be operably coupled together by, for example, one or more timing belts, chains, or gears driven by a single motor. Moreover, the particular angular and/or longitudinal positions of the individual rod journals 448 a-c on the first crankshaft 446 a, and/or the individual rod journals 448 d-f on the second crankshaft 446 b, are not limited to the particular embodiment illustrated in FIGS. 5A and 5B. In other embodiments, for example, the rod journals 448 a-c can be in different angular positions on the first crankshaft 446 a, and/or the rod journals 448 d-f can be in different angular positions on the second crankshaft 446 b. As set forth above, however, one underlying aspect of this embodiment of the technology disclosed herein is that the six rod journals 448 a-f are arranged on their respective crankshafts 446 a, b, and the crankshafts 446 a, b are phased with respect to each other, so that the corresponding plungers 466 a-f (FIG. 4A) reciprocate in evenly spaced apart cycles that occur every 60 degrees of simultaneous rotation of the two crankshafts. This plunger timing can be accomplished with crankshaft arrangements that differ from that illustrated in FIGS. 5A and 5B, without departing from the present technology. By way of example, it is contemplated that the first connecting rod journal 448 a can be positioned at an angle of 0/360 degrees, the second connecting rod journal 448 b can be positioned at an angle of 60 degrees, and the third connecting rod journal 448 c can be positioned at an angle of 120 degrees. Turning next to the second crankshaft 446 b of this example, the fourth connecting rod journal 448 d can be located at an angle of 180 degrees, the fifth connecting rod journal 448 e can be located at an angle of 240 degrees, and the sixth connecting rod journal 448 f can be located at an angle of 300 degrees. It should be noted, however, that although the crankshaft arrangement of this particular example may produce evenly spaced apart plunger cycles of 60 degrees, it may not be practical due to dynamic imbalance of the crankshafts and/or other considerations.

FIG. 6 is a partially schematic top view of a multiplex pump system 640 configured in accordance with another embodiment of the present technology. More specifically, in the illustrated embodiment the multiplex pump system 640 is a quadruplex pump system composed of a first duplex pump 643 a (i.e., a two-cylinder pump) and a second duplex pump 643 b which have their respective crankshafts 646 a, b operably coupled to a shared drive system 680. In some embodiments, the duplex pumps 643 a, b can be substantially identical, or at least generally similar, in structure and function. Many features of the quadruplex pump system 640 can be at least generally similar in structure and function to corresponding features of the sextuplex pump system 340 described in detail above with reference to FIGS. 3A-5B. For example, in the illustrated embodiment the drive system 680 includes a motor 681 (e.g., an electric motor of 50 HP, 100 HP or other suitable capacity, an internal combustion engine, etc.) having two output shaft portions 684 a, b that rotate in unison at the same RPM. The first output shaft portion 684 a is operably coupled to the first crankshaft 646 a by means of a first drive member 682 a (e.g., a continuous timing belt, chain, gears or a gear train, etc.), and the second output shaft portion 684 b is operably coupled to the second crankshaft 646 b by means of a second drive member 682 b.

In the illustrated embodiment, each of the positive displacement duplex pumps 643 a, b includes two plungers 666 a, b and 666 c, d, respectively, which reciprocate in corresponding cylinders 642 a, b and 642 c, d, respectively. The first and second cylinders 642 a, b are mounted to a first crankcase 644 a, and the second and third cylinders 642 c, d are mounted to a second crankcase 644 b. The first and second plungers 666 a, b are operably coupled (e.g., by connecting rods, etc.) to corresponding first and second rod journals 648 a, b, respectively, on the first crankshaft 646 a, and the third and fourth plungers 666 c, d are similarly coupled to corresponding third and fourth journals 648 c, d, respectively, on the second crankshaft 646 b. During pump operation, the cylinders 642 a-d can receive relatively low pressure water via a series of inlets 658 a-d, respectively, and provide high pressure water to manifolds 652 a, b in the manner described above for the sextuplex pump system 340 of FIGS. 3A-5B. For example, the pump cylinders 642 a-d can provide high and/or ultrahigh pressure water at a pressure suitable for, e.g., waterjet processing. The pressure can be, for example, greater than 20,000 psi (e.g., within a range from 20,000 psi to 150,000 psi), greater than 30,000 psi (e.g., within a range from 30,000 psi to 150,000 psi), greater than 60,000 psi (e.g., within a range from 60,000 psi to 150,000 psi). In other embodiments, the pump cylinders 642 a-d can provide water at a pressure greater than another suitable threshold pressure or within another suitable pressure range.

In one aspect of this embodiment, the first and second crankshafts 646 a, b are coupled to the drive system 680 in such a way that the reciprocation cycles of the four plungers 666 a-d occur 90 degrees out of phase from one another during simultaneous rotation of the crankshafts 646 a, b. For example, in the illustrated embodiment the first and second rod journals 648 a, b on the first crankshaft 646 a are spaced apart by angles of 180 degrees relative to each other, and the third and fourth rod journals 648 c, d on the second crankshaft 646 b are also spaced apart by angles of 180 degrees relative to each other. Furthermore, the first crankshaft 646 a is operably coupled to the first output shaft portion 684 a so that it is 90 degrees out of phase from the second crankshaft 646 b when the second crankshaft 646 b is operably coupled to the second output shaft portion 684 b. This arrangement positions both the first and second journals 648 a, b on the first crankshaft 646 a at 90 degree angles relative to the third and fourth journals 648 c, d on the second crankshaft 646 b. As a result, the individual reciprocation cycles of the plungers 666 a-d will occur at equal (or at least approximately equal) 90 degree timing intervals during simultaneous rotation of the coupled crankshafts 646 a, b about their respective longitudinal axes 690 a, b. Accordingly, for purposes of this discussion the quadruplex pump system 640 can exhibit the pressure ripple characteristics or profile as represented by the plots 106 b and 216 b illustrated in FIGS. 1 and 2B, respectively.

The concepts described herein of coupling two duplex or triplex pumps together at fixed phase angles between the respective crankshafts to produce uniformly spaced plunger (or piston) timing and reduce pressure ripples can be extended to other pumps with additional cylinders. For example, the two crankshafts of two respective quadruplex pumps (i.e., pumps with four cylinders) can be coupled together in the manner described above at a fixed phase angle of 45 degrees to produce an eight-cylinder pump having equally spaced plunger/piston timing of 45 degrees. Similarly, the two crankshafts of two respective quintuplex pumps (i.e., pumps with five cylinders) can be coupled together at a fixed phase angle of 36 degrees to produce a ten-cylinder pump having equally spaced plunger/piston timing of 36 degrees. Accordingly, it is expected that other multi-cylinder pumps can be coupled together by phasing the crankshaft angles in the manner described above to produce evenly spaced pressure pulses, and thereby reduce pressure ripple at high and ultrahigh pressures.

One of the advantages of the methods described above for producing multiplex pumps is that rather than simply connecting two pumps together in arbitrary crankshaft relationships, the multiplex pumps described herein can double the power output of the individual pumps while at the same time reducing the magnitude of the output pressure ripple in relatively high pressure regimes. More specifically, by providing equal (or at least approximately equal) timing between plunger/piston cycles (and the corresponding pressure pulses), the multiplex pumps described herein can produce lower pressure ripple than if the crankshafts of the same two pumps were coupled together without regard to the phase relationship.

FIG. 7 is a perspective view of a waterjet system 700 configured in accordance with an embodiment of the present technology. The waterjet system 700 includes a fluid-pressurizing system 702 (shown schematically) configured to pressurize a process fluid (e.g., water) to a pressure suitable for waterjet processing. In some embodiments, the fluid-pressurizing system 702 can include a multiplex pump system configured in accordance with the present technology. For example, the fluid pressurizing system 702 can include a sextuplex or a quadruplex pump system that is at least generally similar in structure and/or function to the sextuplex or quadruplex pump systems 340 and 640 described in detail above with reference to FIGS. 3A-6. The waterjet system 700 can further include a waterjet assembly 704 operably connected to the fluid-pressurizing system 702 via a conduit 706 extending between the fluid pressurizing system 702 and the waterjet assembly 704. In the illustrated embodiment, the conduit 706 is also connected in fluid communication to a safety valve 732 and a relief valve 734. The safety valve 732 and the relief valve 734 can be at least generally similar in structure and/or function to the safety valve 353 and the relief valve 354, respectively, described above with reference to FIGS. 3A-3C.

The waterjet assembly 704 can include a jet outlet 708 and a control valve 710 upstream from the jet outlet 708. The control valve 710 can be at least generally similar in structure and/or function to one or more of the control valves described in U.S. patent application Ser. No. 13/969,477, titled “CONTROL VALVES FOR WATERJET SYSTEMS AND RELATED DEVICES, SYSTEMS, AND METHODS,” filed on Aug. 16, 2013, and incorporated herein in its entirety by reference. For example, the control valve 710 can be configured to receive fluid from the fluid-pressurizing system 702 via the conduit 706 at a pressure suitable for waterjet processing (e.g., a pressure greater than 30,000 psi) and to selectively reduce the pressure of the fluid as the fluid flows through the control valve 710 toward the jet outlet 708. For example, in some embodiments the waterjet assembly 704 can include a first actuator 712 configured to control the position of a pin (not shown) within the control valve 710 and thereby selectively reduce the pressure of the fluid.

The waterjet system 700 can further include a user interface 716 supported by a base 714, and a second actuator 718 configured to move the waterjet assembly 704 relative to the base 714 and other stationary components of the waterjet system 700 (e.g., the fluid-pressurizing system 702). For example, the second actuator 718 can be configured to move the waterjet assembly 704 along a processing path (e.g., cutting path) in two or three dimensions and, in at least some cases, to tilt the waterjet assembly 704 relative to the base 714. The conduit 706 can include a joint 719 (e.g., a swivel joint or another suitable joint having two or more degrees of freedom) configured to facilitate movement of the waterjet assembly 704 relative to the base 714. Thus, the waterjet assembly 704 can be configured to direct a jet, including the fluid toward a workpiece (not shown) supported by the base 714 (e.g., held in a jig supported by the base 714) and to move relative to the base 714 while directing the jet toward the workpiece.

The waterjet system 700 can further include an abrasive-delivery apparatus 720 configured to feed particulate abrasive material from an abrasive material source 721 to the waterjet assembly 704 (e.g., partially or entirely in response to a Venturi effect associated with a fluid jet passing through the waterjet assembly 704). Within the waterjet assembly 704, the particulate abrasive material can accelerate with the jet before being directed toward the workpiece through the jet outlet 708. In some embodiments the abrasive-delivery apparatus 720 is configured to move with the waterjet assembly 704 relative to the base 714. In other embodiments, the abrasive-delivery apparatus 720 can be configured to be stationary while the waterjet assembly 704 moves relative to the base 714. The base 714 can include a diffusing tray 722 configured to hold a pool of fluid positioned relative to the jig so as to diffuse kinetic energy of the jet from the waterjet assembly 704 after the jet passes through the workpiece.

The system 700 can also include a controller 724 (shown schematically) operably connected to the user interface 716, the first actuator 712, the second actuator 718, and the relief valve 734. In some embodiments, the controller 724 is also operably connected to an abrasive-metering valve 726 (shown schematically) of the abrasive-delivery apparatus 720. In other embodiments, the abrasive-delivery apparatus 720 can be without the abrasive-metering valve 726 or the abrasive-metering valve 726 can be configured for use without being operably associated with the controller 724. The controller 724 can include a processor 728 and memory 730 and can be programmed with instructions (e.g., non-transitory instructions contained on a computer-readable medium) that, when executed, control operation of the system 700. For example, the controller 724 can control operation of the control valve 710 (via the first actuator 712) in concert with operation of the relief valve 734 to decrease the pressure of fluid downstream from the control valve 710 while the pressure of fluid upstream from the control valve remains relatively constant.

This disclosure is not intended to be exhaustive or to limit the present technology to the precise forms disclosed herein. Although specific embodiments are disclosed herein for illustrative purposes, various equivalent modifications are possible without deviating from the present technology, as those of ordinary skill in the relevant art will recognize. Accordingly, this disclosure and associated technology can encompass other embodiments not expressly shown or described herein. In some cases, well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of embodiments of the present technology. Although steps of methods may be presented herein in a particular order, in alternative embodiments, the steps may have another suitable order. Similarly, certain aspects of the present technology disclosed in the context of particular embodiments can be combined or eliminated in other embodiments. Furthermore, while advantages associated with certain embodiments may have been disclosed in the context of those embodiments, other embodiments can also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages or other advantages disclosed herein to fall within the scope of the present technology.

It should be noted that other embodiments in addition to those disclosed herein are within the scope of the present technology. For example, embodiments of the present technology can have different configurations, components, and/or procedures than those shown or described herein. Moreover, a person of ordinary skill in the art will understand that embodiments of the present technology can have configurations, components, and/or procedures in addition to those shown or described herein and that these and other embodiments can be without several of the configurations, components, and/or procedures shown or described herein without deviating from the present technology.

Certain aspects of the present technology may take the form of computer-executable instructions, including routines executed by a controller or other data processor. In some embodiments, a controller or other data processor is specifically programmed, configured, or constructed to perform one or more of these computer-executable instructions. Furthermore, some aspects of the present technology may take the form of data (e.g., non-transitory data) stored or distributed on computer-readable media, including magnetic or optically readable or removable computer discs, as well as media distributed electronically over networks. Accordingly, data structures and transmissions of data particular to aspects of the present technology are encompassed within the scope of the present technology. The present technology also encompasses methods of both programming computer-readable media to perform particular steps and executing the steps. The methods disclosed herein include and encompass, in addition to methods of making and using the disclosed apparatuses and systems, methods of instructing others to make and use the disclosed apparatuses and systems.

Throughout this disclosure, the singular terms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. Similarly, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Additionally, the terms “comprising” and the like are used throughout this disclosure to mean including at least the recited feature(s) such that any greater number of the same feature(s) and/or one or more additional types of features are not precluded. Directional terms, such as “upper,” “lower,” “front,” “back,” “vertical,” and “horizontal,” may be used herein to express and clarify the relationship between various elements. It should be understood that such terms do not denote absolute orientation. Reference herein to “one embodiment,” “an embodiment,” or similar formulations means that a particular feature, structure, operation, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present technology. Thus, the appearances of such phrases or formulations herein are not necessarily all referring to the same embodiment. Furthermore, various particular features, structures, operations, or characteristics may be combined in any suitable manner in one or more embodiments.

References throughout the foregoing description to features, advantages, or similar language do not imply that all of the features and advantages that may be realized with the present technology should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present technology. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but does not necessarily, refer to the same embodiment.

From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the various embodiments of the invention. Accordingly, the invention is not limited, except as by the appended claims. Although certain aspects of the invention may be presented below in certain claim forms, the applicant contemplates the various aspects of the invention in any number of claim forms. Accordingly, the applicant reserves the right to pursue additional claims after filing this application to pursue such additional claim forms. 

1-12. (canceled)
 13. A fluid pressurizing system comprising: a first pump, the first pump having: a first crankcase; a first crankshaft operably disposed within the crankcase; at least first and second pressurizing members operably coupled to the first crankshaft; and at least first and second cylinders mounted to the first crankcase, wherein the first pressurizing member is operably disposed in the first cylinder and the second pressurizing member is operably disposed in the second cylinder; a second pump, the second pump having: a second crankcase; a second crankshaft operably disposed within the crankcase; at least third and fourth pressurizing members operably coupled to the second crankshaft; and at least third and fourth cylinders mounted to the second crankcase, wherein the third pressurizing member is operably disposed in the third cylinder and the fourth pressurizing member is operably disposed in the fourth cylinder; a drive system, wherein the first and second crankshafts are operably coupled to the drive system in a fixed phase relationship, and wherein the first, second, third and fourth pressurizing members reciprocate in the corresponding first, second, third and fourth cylinders in cycles spaced apart by equal phase angles during simultaneous rotation of the first and second crankshafts; a first manifold in fluid communication with the first and second cylinders; a second manifold in fluid communication with the third and fourth cylinders; and a fluid junction operably coupled in fluid communication with the first manifold via a first conduit and the second manifold via a second conduit, wherein the first conduit is substantially equivalent to the second conduit in length, internal flow area, or both.
 14. The fluid pressurizing system of claim 13 wherein the first conduit has a first length and the second conduit has a second length that is substantially equivalent to the first length.
 15. The fluid pressurizing system of claim 13 wherein the first conduit has a first length and a first internal flow area, and wherein the second conduit has a second length that is substantially equivalent to the first length and a second internal flow area that is substantially equivalent to the first internal flow area.
 16. The fluid pressurizing system of claim 13, wherein the first crankshaft includes first and second journals offset from each other by a phase angle of 180 degrees, and wherein the first and second pressurizing members are operably coupled to the first and second journals, respectively; wherein the second crankshaft includes third and fourth journals offset from each other by a phase angle of 180 degrees, and wherein the third and fourth pressurizing members are operably coupled to the third and fourth journals, respectively; and wherein the first and second crankshafts are operably coupled to the drive system so that the reciprocation cycles of the first, second, third and fourth pressurizing members occur sequentially at 90 degree intervals during synchronized rotation of the first and second crankshafts.
 17. The fluid pressurizing system of claim 13, wherein the first pump further includes: a fifth pressurizing member operably coupled to the first crankshaft; and a fifth cylinder mounted to the first crankcase, wherein the fifth pressurizing member is operably disposed in the fifth cylinder; wherein the second pump further includes: a sixth pressurizing member operably coupled to the second crankshaft; and a sixth cylinder mounted to the second crankcase, wherein the sixth pressurizing member is operably disposed in the sixth cylinder; wherein the first crankshaft includes first, second and third journals offset from one another by crankshaft angles of 120 degrees, and wherein the first, second and fifth pressurizing members are operably coupled to the first, second and third journals, respectively; wherein the second crankshaft includes fourth, fifth and sixth journals offset from one another by crankshaft angles of 120 degrees, and wherein the fourth, fifth and sixth pressurizing members are operably coupled to the fourth, fifth and sixth journals, respectively; and wherein the first and second crankshafts are operably coupled to the drive system at a fixed phase angle of 60 degrees.
 18. The fluid pressurizing system of claim 13 wherein the first and second pumps provide process fluid to the junction at pressures greater than 30,000 psi with a fixed crankshaft phase angle of 60 degrees between pressure pulses when driven by the drive system.
 19. The fluid pressurizing system of claim 13 wherein the first and second pumps provide process fluid at pressures greater than 60,000 psi and less than 150,000 psi with a fixed crankshaft phase angle of 60 degrees between pressure pulses when driven by the drive system.
 20. The fluid pressurizing system of claim 13 wherein the drive system includes a motor having first and second output shaft portions, wherein the first crankshaft is operably coupled to the first output shaft portion by a first drive member, and wherein the second crankshaft is operably coupled to the second output shaft portion by a second drive member.
 21. The fluid pressurizing system of claim 13 wherein the pressurizing members are plungers.
 22. The fluid pressurizing system of claim 13 wherein the pressurizing members are pistons. 23-27. (canceled)
 28. A method of assembling a waterjet system, the method comprising: operably coupling a first crankshaft of a first pump to a drive system, the first pump having at least a first high pressure fluid outlet; operably coupling a second crankshaft of a second pump to the drive system, the second pump having at least a second high pressure fluid outlet; operably coupling the first high pressure fluid outlet to a fluid junction via a first conduit, the first conduit having a first length and a first internal cross-sectional area; operably coupling the second high pressure fluid outlet to the fluid junction via a second conduit, the second conduit having a second length that is at least substantially equivalent to the first length and a second internal cross-sectional area that is at least substantially equivalent to the first internal cross-sectional area; and operably coupling a third conduit between the fluid junction and a waterjet nozzle assembly, wherein the third conduit is configured to convey high pressure fluid from the fluid junction to the nozzle assembly for directing onto a workpiece by a cutting head.
 29. The method of claim 28 wherein operably coupling the first and second crankshafts to the drive system includes operably coupling the first and second crankshafts to the drive system in a fixed phase relationship.
 30. The method of claim 28 wherein operably coupling the first and second crankshafts to the drive system includes operably coupling the first and second crankshafts to the drive system in a fixed phase relationship that causes the first and second pumps to provide the high pressure fluid to the fluid junction with uniformly spaced pressure pulsations during operation of the drive system.
 31. The method of claim 28 wherein operably coupling the first and second crankshafts to the drive system includes operably coupling the first and second crankshafts to the drive system in a fixed phase relationship that causes the first and second pumps to provide the high pressure fluid to the fluid junction at a pressure greater than 30,000 psi and less than 150,000 psi, and with uniformly spaced pressure pulsations, during operation of the drive system.
 32. The method of claim 28 wherein the first pump is a first triplex pump and the second pump is a second triplex pump.
 33. The method of claim 28 wherein the first pump is a first duplex pump and the second pump is a second duplex pump, and wherein operably coupling the first and second crankshafts to the drive system includes operably coupling the first and second crankshafts to the drive system at a fixed phase angle of 90 degrees.
 34. The method of claim 28 wherein the first pump is a first triplex pump and the second pump is a second triplex pump, and wherein operably coupling the first and second crankshafts to the drive system includes operably coupling the first and second crankshafts to the drive system at a fixed phase angle of 60 degrees. 35-86. (canceled)
 87. A method of producing a fluid pressurizing system, the method comprising: operably coupling a first crankshaft of a first multiplex pump to a drive system; and operably coupling a second crankshaft of a second multiplex pump to the drive system in a fixed phase relationship to the first crankshaft.
 88. The method of claim 87: wherein the first multiplex pump includes a first plurality of compression members operably coupled to the first crankshaft; wherein the second multiplex pump includes a second plurality of compression members operably coupled to the second crankshaft; and wherein operably coupling the second crankshaft to the drive system includes positioning the second crankshaft relative to the first crankshaft so that the first and second pluralities of compression members reciprocate in evenly spaced apart cycles during simultaneous rotation of the first and second crankshafts by the drive system.
 89. The method of claim 87, further comprising operating the drive system to pressurize and discharge process fluid from the first and second multiplex pumps at pressures greater than 20,000 psi and less than 150,000 psi. 90-111. (canceled) 